Have a look at this site and it will tell you a bit more about the smc.ac "scam".

http://www.russellbeattie.com/notebook/1008290.html

http://joi.ito.com/archives/2005/02/...ith_smsac.html

Seems like they will continue to send messages and charge the users even if they didn't want messages sent anymore. Sounds like the AOL "Free Trial Period".